so i won a GM tourney and as prize they give me a item named Shiai Token, but i have no idea What does this do, someone could say me?

A Shiai Token is like a coin that you can use to buy some items.
Read this thread for more information.
http://forum.toribash.com/showthread.php?t=448147

It's for buying 3D items. You can only obtain it by GMtourneys, and it's rare.